The invention relates to a fault-tolerant actuating system for adjusting flaps of an aircraft, comprising adjustment kinematics with a fixed pivot, and a method for monitoring an actuating system.
By means of the fault-tolerant actuating system for adjusting flaps of an aircraft a number of predetermined failures of components of the actuating system can be compensated for.
Document EP 1 739 009A1 describes an electric control surface actuation system for aircraft flaps and slats. Document EP 1 640 265A1 discloses a control system for a horizontal stabilizer of an aircraft. From the state of the art the adjustment system shown in FIG. 1 is known, with the high-lift system 1 shown in the figure being provided for adjusting at least one landing flap on each wing. FIG. 1 shows two landing flaps for each wing, wherein the wing is not shown in FIG. 1. The following are shown in detail: an inner landing flap A1 and an outer landing flap A2 on a first wing, and an inner landing flap B1 and an outer landing flap B2 on a second wing. In the high-lift system according to the invention it is also possible to use more than two landing flaps for each wing. The high-lift system 1 is operated and controlled by way of a pilot interface that, in particular, comprises an actuating member 3, for example an actuating lever. The actuating member 3 is functionally coupled to a control and monitoring device 5 that transmits control commands by way of a control line 8 for controlling a central drive unit 7.
The drive unit 7, which is arranged centrally, in other words in the fuselage region, comprises two drive motors, for example a hydraulic motor H and an electric drive E, as well as brake mechanisms B1, B2 that are associated with the aforesaid. Furthermore, the central drive unit 7 comprises a differential. The differential is coupled to the output sides of the hydraulic motor M1 and of the electric motor M2 in such a manner that the outputs delivered by the hydraulic motor H and the electric motor are in each case summed, and are transmitted to rotary drive shafts 11, 12. The brake mechanisms B1, B2 can be operated by means of a command signal from the control and monitoring device 5.
For each wing a total of two rotary drive shafts 11, 12, each provided for operating the at least one flap A1, A2 or B1, B2, are coupled to the central drive unit 7. The two rotary drive shafts 11, 12 are coupled to the central drive unit 7 and are synchronised by said drive unit 7. On the basis of corresponding control commands the central drive unit 7 causes the rotary drive shafts 11, 12 to rotate in order to carry out actuating movements of the adjustment devices, which are coupled to the aforesaid, of the respective flap. A torque limiter T can be integrated in a shaft section of the rotary drive shafts 11, 12, which shaft section is situated near the drive unit 7.
On each flap A1, A2 or B1, B2 two adjustment devices are provided. In the high-lift system shown in FIG. 1, on each flap two adjustment devices are arranged, namely the adjustment devices A11, A12 or B11, B12 on the inner flaps A1 and B1, and the adjustment devices A21, A22 or B21, B22 on the outer flaps A2 and B2.
Below, there is a description of the adjustment devices A11, A12, B11, B12, A21, A22, B21, B22, wherein the components of various adjustment devices with the same function in each adjustment device comprise the same reference characters.
Each one of the adjustment devices A11, A12, B11, B12, A21, A22, B21, B22 is associated with a transmission gear unit 20, adjustment kinematics 21 with a fixed centre of flap rotation, and a position sensor 22. The transmission gear unit 20 is mechanically coupled to the respective rotary drive shafts 11, 12 and translates a rotary movement of the respective rotary drive shafts 11, 12 to an adjustment movement of the flap region that is coupled to the respective adjustment devices A11, A12, B11, B12, A21, A22, B21, B22. On each adjustment device A11, A12, B11, B12, A21, A22, B21, B22 of a flap a position sensor 22 is arranged that determines the current position of the respective flap and transmits this position value, by way of a line (not shown), to the control and monitoring device 5.
In addition, on the ends of the rotary-shaft drive trains 11 or 12 an asymmetry sensor 23 is arranged, which is also functionally connected, by way of a line (not shown), to the control and monitoring device 5, and by way of this line transmits a current value to the control and monitoring device 5, which value states whether the ends of the rotary-shaft drive trains 11 or 12 are rotated within a predetermined region, or whether an asymmetrical rotary position of the rotary drive shafts 11 or 12 exists.
Furthermore, at a position of the rotary drive shafts 11 or 12 that is situated in an outer region of the respective wing, in each case a wing-end region brake WTB is arranged which when activated can block the respective drive train 11 or 12. Each of the wing-end region brakes WTB is functionally connected, by way of a line (not shown either), to the control and monitoring device 5, and by way of this line can be controlled and activated by the control and monitoring device 5. In operation the normal initial state of the wing-end region brake WTB is a non-activated state in which said brake does not intervene with the rotation of the rotary drive shafts 11 or 12. In the case of a corresponding control signal from the control and monitoring device 5 the wing-end region brakes WTB can be activated in order to stop rotation of the respectively associated rotary drive shafts 11 or 12.
Both brake mechanisms B1, B2 are functionally connected to the control and monitoring device 5 which when predetermined conditions are met can operate the brake mechanisms B1, B2 and in so doing can stop rotation of the rotary-shaft drive trains 11, 12. If one of the two drive motors, the hydraulic motor H or the electric drive E is switched off, because of the differential, which is designed in such a way that the outputs provided by the hydraulic motor H and the electric motor are summed, the central drive unit 7 provides an output that is reduced by the amount from the switched-off drive motor.
Mechanical faults in the flap actuating mechanisms A11, A12, A21, A22, B11, B12, B21, B22, for example any jamming of a component of a flap actuating mechanism or of the rotary-shaft drive trains 11, 12 or any failure of a rotary drive shaft of a rotary-shaft drive train 11, 12 can result in undesirable behaviour of the device, for example asymmetrical operation of the flap elements, which will be detected by the control and monitoring device 5 by means of the signals transmitted by the asymmetry sensors 23. Thereafter, the control computer 5 transmits a switch-off signal to the wing-end region brake WTB in order to activate the wing-end region brakes WTB and to stop rotation of the rotary drive shafts 11, 12.
If there is an inadmissible difference between the desired positions determined by the control and monitoring device 5 and the actual positions determined by the position sensors 22, the control and monitoring device 5 transmits an actuating signal to the wing-end region brake WTB and to the brake mechanisms B1, B2 in order to stop rotation of both shaft drive trains 11, 12.